2 files changed, 345 insertions, 6 deletions

diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c
index 354f170eab95..4894bde4bbff 100644
--- a/drivers/spi/spi-rspi.c
+++ b/drivers/spi/spi-rspi.c
@@ -31,7 +31,11 @@
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/clk.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/sh_dma.h>
 #include <linux/spi/spi.h>
+#include <linux/spi/rspi.h>
 
 #define RSPI_SPCR               0x00
 #define RSPI_SSLP               0x01
@@ -141,6 +145,16 @@ struct rspi_data {
         spinlock_t lock;
         struct clk *clk;
         unsigned char spsr;
+
+        /* for dmaengine */
+        struct sh_dmae_slave dma_tx;
+        struct sh_dmae_slave dma_rx;
+        struct dma_chan *chan_tx;
+        struct dma_chan *chan_rx;
+        int irq;
+
+        unsigned dma_width_16bit:1;
+        unsigned dma_callbacked:1;
 };
 
 static void rspi_write8(struct rspi_data *rspi, u8 data, u16 offset)
@@ -265,11 +279,125 @@ static int rspi_send_pio(struct rspi_data *rspi, struct spi_message *mesg,
         return 0;
 }
 
-static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg,
-                            struct spi_transfer *t)
+static void rspi_dma_complete(void *arg)
+{
+        struct rspi_data *rspi = arg;
+
+        rspi->dma_callbacked = 1;
+        wake_up_interruptible(&rspi->wait);
+}
+
+static int rspi_dma_map_sg(struct scatterlist *sg, void *buf, unsigned len,
+                           struct dma_chan *chan,
+                           enum dma_transfer_direction dir)
+{
+        sg_init_table(sg, 1);
+        sg_set_buf(sg, buf, len);
+        sg_dma_len(sg) = len;
+        return dma_map_sg(chan->device->dev, sg, 1, dir);
+}
+
+static void rspi_dma_unmap_sg(struct scatterlist *sg, struct dma_chan *chan,
+                              enum dma_transfer_direction dir)
+{
+        dma_unmap_sg(chan->device->dev, sg, 1, dir);
+}
+
+static void rspi_memory_to_8bit(void *buf, const void *data, unsigned len)
+{
+        u16 *dst = buf;
+        const u8 *src = data;
+
+        while (len) {
+                *dst++ = (u16)(*src++);
+                len--;
+        }
+}
+
+static void rspi_memory_from_8bit(void *buf, const void *data, unsigned len)
+{
+        u8 *dst = buf;
+        const u16 *src = data;
+
+        while (len) {
+                *dst++ = (u8)*src++;
+                len--;
+        }
+}
+
+static int rspi_send_dma(struct rspi_data *rspi, struct spi_transfer *t)
+{
+        struct scatterlist sg;
+        void *buf = NULL;
+        struct dma_async_tx_descriptor *desc;
+        unsigned len;
+        int ret = 0;
+
+        if (rspi->dma_width_16bit) {
+                /*
+                 * If DMAC bus width is 16-bit, the driver allocates a dummy
+                 * buffer. And, the driver converts original data into the
+                 * DMAC data as the following format:
+                 *  original data: 1st byte, 2nd byte ...
+                 *  DMAC data:     1st byte, dummy, 2nd byte, dummy ...
+                 */
+                len = t->len * 2;
+                buf = kmalloc(len, GFP_KERNEL);
+                if (!buf)
+                        return -ENOMEM;
+                rspi_memory_to_8bit(buf, t->tx_buf, t->len);
+        } else {
+                len = t->len;
+                buf = (void *)t->tx_buf;
+        }
+
+        if (!rspi_dma_map_sg(&sg, buf, len, rspi->chan_tx, DMA_TO_DEVICE)) {
+                ret = -EFAULT;
+                goto end_nomap;
+        }
+        desc = dmaengine_prep_slave_sg(rspi->chan_tx, &sg, 1, DMA_TO_DEVICE,
+                                       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+        if (!desc) {
+                ret = -EIO;
+                goto end;
+        }
+
+        /*
+         * DMAC needs SPTIE, but if SPTIE is set, this IRQ routine will be
+         * called. So, this driver disables the IRQ while DMA transfer.
+         */
+        disable_irq(rspi->irq);
+
+        rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) | SPCR_TXMD, RSPI_SPCR);
+        rspi_enable_irq(rspi, SPCR_SPTIE);
+        rspi->dma_callbacked = 0;
+
+        desc->callback = rspi_dma_complete;
+        desc->callback_param = rspi;
+        dmaengine_submit(desc);
+        dma_async_issue_pending(rspi->chan_tx);
+
+        ret = wait_event_interruptible_timeout(rspi->wait,
+                                               rspi->dma_callbacked, HZ);
+        if (ret > 0 && rspi->dma_callbacked)
+                ret = 0;
+        else if (!ret)
+                ret = -ETIMEDOUT;
+        rspi_disable_irq(rspi, SPCR_SPTIE);
+
+        enable_irq(rspi->irq);
+
+end:
+        rspi_dma_unmap_sg(&sg, rspi->chan_tx, DMA_TO_DEVICE);
+end_nomap:
+        if (rspi->dma_width_16bit)
+                kfree(buf);
+
+        return ret;
+}
+
+static void rspi_receive_init(struct rspi_data *rspi)
 {
-        int remain = t->len;
-        u8 *data;
         unsigned char spsr;
 
         spsr = rspi_read8(rspi, RSPI_SPSR);
@@ -278,6 +406,15 @@ static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg,
         if (spsr & SPSR_OVRF)
                 rspi_write8(rspi, rspi_read8(rspi, RSPI_SPSR) & ~SPSR_OVRF,
                             RSPI_SPCR);
+}
+
+static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg,
+                            struct spi_transfer *t)
+{
+        int remain = t->len;
+        u8 *data;
+
+        rspi_receive_init(rspi);
 
         data = (u8 *)t->rx_buf;
         while (remain > 0) {
@@ -307,6 +444,120 @@ static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg,
         return 0;
 }
 
+static int rspi_receive_dma(struct rspi_data *rspi, struct spi_transfer *t)
+{
+        struct scatterlist sg, sg_dummy;
+        void *dummy = NULL, *rx_buf = NULL;
+        struct dma_async_tx_descriptor *desc, *desc_dummy;
+        unsigned len;
+        int ret = 0;
+
+        if (rspi->dma_width_16bit) {
+                /*
+                 * If DMAC bus width is 16-bit, the driver allocates a dummy
+                 * buffer. And, finally the driver converts the DMAC data into
+                 * actual data as the following